A Geospatial Assessment of Flood Vulnerability Reduction by Freshwater Wetlands–A Benefit Indicators Approach

Abstract

Flooding is among the most common and costly natural disasters in the United States. Flood impacts have been on the rise as flood mitigating habitats are lost, development places more people and infrastructure potentially at risk, and changing rainfall results in altered flood frequency. Across the nation, communities are recognizing the value of flood mitigating habitats and employing green infrastructure alternatives, including restoring some of those ecosystems, as a way to increase resilience. However, communities may under value green infrastructure, because they do not recognize the current benefits of risk reduction they receive from existing ecosystems or the potential benefits they could receive through restoration. Freshwater wetlands have long been recognized as one of the ecosystems that can reduce flood damages by attenuating surface water. Small-scale community studies can capture the flood-reduction benefits from existing or potentially restored wetlands. However, scalability and transferability are limits for these high resolution and data intensive studies. This paper details the development of a nationally consistent dataset and a set of high-resolution indicators characterizing where people benefit from reduced flood risk through existing wetlands. We demonstrate how this dataset can be used at different scales (regional or local) to rapidly assess flood-reduction benefits. At a local scale we use other national scale indicators (CRSI, SoVI) to gauge community resilience and recoverability to choose Harris County, Texas as our focus. Analysis of the Gulf Coast region and Harris County, Texas identifies communities with both wetland restoration potential and the greatest flood-prone population that could benefit from that restoration. We show how maps of these indicators can be used to set wetland protection and restoration priorities.

Evaluating the ecosystem services and benefits of wetland restoration by use of the rapid benefit indicators approach

“…Quality of the service This indicator evaluates the quality of a service, assuming that higher quality services have greater value. An indicator of quality might be based on scores from a functional assessment, on location‐specific models or expert elicitation (Radford and James ; Bousquin et al ), or on literature that relates people's preferences to services and benefits (Van Herzele and Wiedemann ; Wolf ). For example, when comparing the scenic quality of 2 locations, quality indicators could be based on factors such as the presence of open water, an attribute that people often say adds to scenic beauty, or presence of industrial buildings, a feature that detracts from scenic beauty (Gobster and Westphal ; Dramstad et al ). B.…”

Rapid Benefit Indicator Tools

“…The Rapid Benefit Indicators (RBI) catchment dataset 3 allows a user to compare sites in different catchments based on a catchment characterization previously performed using a sub-set of indicator metrics (Bousquin and Hychka 2019). Rather than being a tool to help users analyze their data, this is a national dataset of results for two indicators of reduced flood risk benefits.…”

“…For example, a 10% difference in wetlands between catchments in west Texas is drastic but would be minor in coastal Minnesota. To account for this, Bousquin and Hychka (2019) suggest binning the indicators into discrete categories based on the distribution of regional values, and show a method using four quartiles, dividing catchment values into four categories of equal number. Different discretizations are better suited depending on thresholds, decision context and overarching objectives.…”

Analysis of Wetland Landcover Change in Great Lakes Urban Areas Using Self-Organizing Maps

“…The spatial scale of the wetland benefits is also important to acknowledge, as wetlands that are spatially situated away from areas that experience flooding may still be providing benefits and reducing the impacts of the flood [14]. Generally, the benefits of wetlands that act as a flood reduction service are defined by upstream and downstream landscape characteristics [15]. As the impacts associated with climate change become more prominent, utilizing wetlands as a component of flood control in the Great Lakes region will be particularly important [16].…”